Mirror effect in frequency discrimination

In recognition, types of stimuli that are relatively easy to classify as old when old are also relatively easy to classify as new when new. The experiments reported here extend this mirror effect to discriminations among above-zero situational frequencies. Frequency discrimination exhibits a mirror effect when words are compared with nonwords or when low-linguistic-frequency words are compared with high-linguistic-frequency words. Accurate knowledge concerning the relative memorability of test items is neither necessary nor sufficient for the presence of a mirror effect.